Catheters are often used for the delivery and withdrawal of fluids to and from a blood vessel in a patient, respectively. The fluids may be medication that is administered to the patient, or blood that is withdrawn from the patient. The catheter may also be used for hemodialysis, in which blood is withdrawn from the patient, purified and returned simultaneously through respective lumens of the catheter, and much of the catheter remains within the patient's vasculature for an extended period of time for repeated treatments.
Typically, to insert a catheter into a blood vessel, the blood vessel is located by known methods. An aspirating needle is inserted into the vessel to confirm placement within the vessel. A guide wire is then inserted through a proximal end of the aspirating needle and into the vessel. The aspirating needle is withdrawn by sliding the needle proximally over the guide wire, leaving the guide wire within the vessel. If a catheter with a sufficiently hard wall is being used, the catheter may be slid over the guide wire, directly into the vessel.
However, for some catheters, particularly soft walled catheters, a dilator is required to dilate the vessel at the insertion point in order to accommodate the insertion of the catheter. The dilator is typically inserted into a sheath and initially used as a dilator and sheath assembly. The assembly is inserted into the vessel over the guide wire and the dilator is used to dilate the insertion opening in the vessel wall. After the insertion opening is dilated, the dilator and the guide wire are removed from the vessel by removing both the dilator and the guide wire proximally from the sheath. The sheath remains in the vessel to accommodate insertion of the catheter through the sheath and into the blood vessel.
Additionally, splittable introducer sheaths are known, wherein the sheath can be easily removed from around a catheter assembly inserted thereinto and into the patient's vasculature. Typically, such assemblies include manually grippable tabs or wings at the proximal end of the sheath hub that can be pried apart to initiate splitting of the hub and the attached sheath tube apart while simultaneously pulling it proximally along the catheter and out of the patient.
Conventionally, introducer sheaths have hubs affixed to their proximal ends to which the dilator hub is locked during preparation of the vessel insertion opening. It has become desired for the sheath to be of polytetrafluoroethylene, while the hub material is a different plastic material such as polyethylene. It is known the polytetrafluoroethylene, or PTFE, is notoriously difficult to bond to other plastic materials, so it remains problematic to configure methods and manners of securing the hub to the sheath.
It is desired to provide a simplified method of securing a hub to a PTFE sheath proximal end.
It is further desirable to provide a simplified method of securing a hub to a PTFE sheath proximal end, where the introducer sheath assembly is splittable and the hub component halves must remain affixed to respective halves of the sheath during splitting.